import java.util.Scanner;
public class Homework02 {
	public static void main(String[] args) {
		System.out.print("输入明文：");
		Scanner scanner=new Scanner(System.in);
		String key="abc";
		char[] str=scanner.nextLine().toCharArray();
		char[] keys=key.toCharArray();
		System.out.print("密文是   ：");
		for(int i=0,j=0;i<str.length;i++,j++) {
			if(j==keys.length)   
				j=0;
			int result=(str[i]-'a'+keys[j]-'a')%26+'a';
			System.out.print((char)result);
		}

	}

}
